Evidence supporting this hypothesis includes studies in which mice administered methionine were found to exhibit some of the endophenotypes of schizophrenia [2], as well as studies using animal and cell models demonstrating that the schizophrenia candidate genes the 67 kDa isoform of glutamic acid decarboxylase (GAD67) and reelin are regulated through epigenetic mechanisms [3–5]. This evidence concerns the gene GAD1 and schizophrenia.